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Message-ID: <CANFp7mWvxK5DWJZBqHdJJmjo_X5n5NJv+mZ7U5FQ4Aj7-VRpSw@mail.gmail.com>
Date: Wed, 13 Nov 2024 20:13:26 -0800
From: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: heikki.krogerus@...ux.intel.com, tzungbi@...nel.org,
linux-usb@...r.kernel.org, chrome-platform@...ts.linux.dev, jthies@...gle.com,
akuchynski@...gle.com, pmalani@...omium.org,
Benson Leung <bleung@...omium.org>, Guenter Roeck <groeck@...omium.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 5/7] platform/chrome: cros_ec_typec: Displayport support
On Fri, Nov 8, 2024 at 10:38 PM Dmitry Baryshkov
<dmitry.baryshkov@...aro.org> wrote:
>
> On Thu, Nov 07, 2024 at 11:29:58AM -0800, Abhishek Pandit-Subedi wrote:
> > Add support for entering and exiting displayport alt-mode on systems
> > using AP driven alt-mode.
> >
> > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> > ---
> >
> > Changes in v3:
> > - Refactored typec_altmode_dp_data per review request
> > - Removed unused vdm operations during altmode registration
> >
> > Changes in v2:
> > - Refactored displayport into cros_typec_altmode.c to extract common
> > implementation between altmodes
> >
> > MAINTAINERS | 3 +
> > drivers/platform/chrome/Makefile | 4 +
> > drivers/platform/chrome/cros_ec_typec.c | 12 +-
> > drivers/platform/chrome/cros_ec_typec.h | 1 +
> > drivers/platform/chrome/cros_typec_altmode.c | 275 +++++++++++++++++++
> > drivers/platform/chrome/cros_typec_altmode.h | 34 +++
> > 6 files changed, 326 insertions(+), 3 deletions(-)
> > create mode 100644 drivers/platform/chrome/cros_typec_altmode.c
> > create mode 100644 drivers/platform/chrome/cros_typec_altmode.h
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index cd6aa609deba..5f9d8b8f1cb3 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -5369,9 +5369,12 @@ F: include/linux/platform_data/cros_usbpd_notify.h
> >
> > CHROMEOS EC USB TYPE-C DRIVER
> > M: Prashant Malani <pmalani@...omium.org>
> > +M: Benson Leung <bleung@...omium.org>
> > +M: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> > L: chrome-platform@...ts.linux.dev
> > S: Maintained
> > F: drivers/platform/chrome/cros_ec_typec.*
> > +F: drivers/platform/chrome/cros_typec_altmode.*
> > F: drivers/platform/chrome/cros_typec_switch.c
> > F: drivers/platform/chrome/cros_typec_vdm.*
> >
> > diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> > index 2dcc6ccc2302..2f90d4db8099 100644
> > --- a/drivers/platform/chrome/Makefile
> > +++ b/drivers/platform/chrome/Makefile
> > @@ -18,7 +18,11 @@ obj-$(CONFIG_CROS_EC_SPI) += cros_ec_spi.o
> > obj-$(CONFIG_CROS_EC_UART) += cros_ec_uart.o
> > cros_ec_lpcs-objs := cros_ec_lpc.o cros_ec_lpc_mec.o
> > cros-ec-typec-objs := cros_ec_typec.o cros_typec_vdm.o
> > +ifneq ($(CONFIG_TYPEC_DP_ALTMODE),)
> > + cros-ec-typec-objs += cros_typec_altmode.o
> > +endif
> > obj-$(CONFIG_CROS_EC_TYPEC) += cros-ec-typec.o
> > +
> > obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpcs.o
> > obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o cros_ec_trace.o
> > obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
> > diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> > index e3eabe5e42ac..3a6f5f2717b9 100644
> > --- a/drivers/platform/chrome/cros_ec_typec.c
> > +++ b/drivers/platform/chrome/cros_ec_typec.c
> > @@ -18,6 +18,7 @@
> >
> > #include "cros_ec_typec.h"
> > #include "cros_typec_vdm.h"
> > +#include "cros_typec_altmode.h"
> >
> > #define DRV_NAME "cros-ec-typec"
> >
> > @@ -293,12 +294,11 @@ static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
> > desc.svid = USB_TYPEC_DP_SID;
> > desc.mode = USB_TYPEC_DP_MODE;
> > desc.vdo = DP_PORT_VDO;
> > - amode = typec_port_register_altmode(port->port, &desc);
> > + amode = cros_typec_register_displayport(port, &desc,
> > + typec->ap_driven_altmode);
> > if (IS_ERR(amode))
> > return PTR_ERR(amode);
> > port->port_altmode[CROS_EC_ALTMODE_DP] = amode;
> > - typec_altmode_set_drvdata(amode, port);
> > - amode->ops = &port_amode_ops;
> >
> > /*
> > * Register TBT compatibility alt mode. The EC will not enter the mode
> > @@ -575,6 +575,10 @@ static int cros_typec_enable_dp(struct cros_typec_data *typec,
> > if (!ret)
> > ret = typec_mux_set(port->mux, &port->state);
> >
> > + if (!ret)
> > + cros_typec_displayport_status_update(port->state.alt,
> > + port->state.data);
> > +
> > return ret;
> > }
> >
> > @@ -1254,6 +1258,8 @@ static int cros_typec_probe(struct platform_device *pdev)
> >
> > typec->typec_cmd_supported = cros_ec_check_features(ec_dev, EC_FEATURE_TYPEC_CMD);
> > typec->needs_mux_ack = cros_ec_check_features(ec_dev, EC_FEATURE_TYPEC_MUX_REQUIRE_AP_ACK);
> > + typec->ap_driven_altmode = cros_ec_check_features(
> > + ec_dev, EC_FEATURE_TYPEC_REQUIRE_AP_MODE_ENTRY);
> >
> > ret = cros_ec_cmd(typec->ec, 0, EC_CMD_USB_PD_PORTS, NULL, 0,
> > &resp, sizeof(resp));
> > diff --git a/drivers/platform/chrome/cros_ec_typec.h b/drivers/platform/chrome/cros_ec_typec.h
> > index deda180a646f..9fd5342bb0ad 100644
> > --- a/drivers/platform/chrome/cros_ec_typec.h
> > +++ b/drivers/platform/chrome/cros_ec_typec.h
> > @@ -39,6 +39,7 @@ struct cros_typec_data {
> > struct work_struct port_work;
> > bool typec_cmd_supported;
> > bool needs_mux_ack;
> > + bool ap_driven_altmode;
> > };
> >
> > /* Per port data. */
> > diff --git a/drivers/platform/chrome/cros_typec_altmode.c b/drivers/platform/chrome/cros_typec_altmode.c
> > new file mode 100644
> > index 000000000000..3598b8a6ceee
> > --- /dev/null
> > +++ b/drivers/platform/chrome/cros_typec_altmode.c
> > @@ -0,0 +1,275 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Alt-mode implementation on ChromeOS EC.
> > + *
> > + * Copyright 2024 Google LLC
> > + * Author: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> > + */
> > +#include "cros_ec_typec.h"
> > +
> > +#include <linux/usb/typec_dp.h>
> > +#include <linux/usb/pd_vdo.h>
> > +
> > +#include "cros_typec_altmode.h"
> > +
> > +struct cros_typec_altmode_data {
> > + struct work_struct work;
> > + struct cros_typec_port *port;
> > + struct typec_altmode *alt;
> > + bool ap_mode_entry;
> > +
> > + u32 header;
> > + u32 *vdo_data;
> > + u8 vdo_size;
> > +
> > + u16 sid;
> > + u8 mode;
> > +};
> > +
> > +struct cros_typec_dp_data {
> > + struct cros_typec_altmode_data adata;
> > + struct typec_displayport_data data;
> > + bool configured;
> > + bool pending_status_update;
> > +};
> > +
> > +static void cros_typec_altmode_work(struct work_struct *work)
> > +{
> > + struct cros_typec_altmode_data *data =
> > + container_of(work, struct cros_typec_altmode_data, work);
> > +
> > + if (typec_altmode_vdm(data->alt, data->header, data->vdo_data,
> > + data->vdo_size))
> > + dev_err(&data->alt->dev, "VDM 0x%x failed", data->header);
> > +
> > + data->header = 0;
> > + data->vdo_data = NULL;
> > + data->vdo_size = 0;
>
> What protects data->header / vdo_data / vdo_size from concurrent
> modification?
Good catch! This needs a mutex -- will add for the next series.
>
> > +}
> > +
> > +static int cros_typec_altmode_enter(struct typec_altmode *alt, u32 *vdo)
> > +{
> > + struct cros_typec_altmode_data *data = typec_altmode_get_drvdata(alt);
> > + struct ec_params_typec_control req = {
> > + .port = data->port->port_num,
> > + .command = TYPEC_CONTROL_COMMAND_ENTER_MODE,
> > + };
> > + int svdm_version;
> > + int ret;
> > +
> > + if (!data->ap_mode_entry) {
> > + const struct typec_altmode *partner =
> > + typec_altmode_get_partner(alt);
> > + dev_warn(&partner->dev,
> > + "EC does not support ap driven mode entry\n");
>
> Nit: AP, not ap
Ack for next series.
>
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + if (data->sid == USB_TYPEC_DP_SID)
> > + req.mode_to_enter = CROS_EC_ALTMODE_DP;
> > + else
> > + return -EOPNOTSUPP;
> > +
> > + ret = cros_ec_cmd(data->port->typec_data->ec, 0, EC_CMD_TYPEC_CONTROL,
> > + &req, sizeof(req), NULL, 0);
> > + if (ret < 0)
> > + return ret;
> > +
> > + svdm_version = typec_altmode_get_svdm_version(alt);
> > + if (svdm_version < 0)
> > + return svdm_version;
> > +
> > + data->header = VDO(data->sid, 1, svdm_version, CMD_ENTER_MODE);
> > + data->header |= VDO_OPOS(data->mode);
> > + data->header |= VDO_CMDT(CMDT_RSP_ACK);
> > +
> > + data->vdo_data = NULL;
> > + data->vdo_size = 1;
> > +
> > + schedule_work(&data->work);
> > +
> > + return ret;
> > +}
> > +
> > +static int cros_typec_altmode_exit(struct typec_altmode *alt)
> > +{
> > + struct cros_typec_altmode_data *data = typec_altmode_get_drvdata(alt);
> > + struct ec_params_typec_control req = {
> > + .port = data->port->port_num,
> > + .command = TYPEC_CONTROL_COMMAND_EXIT_MODES,
> > + };
> > + int svdm_version;
> > + int ret;
> > +
> > + if (!data->ap_mode_entry) {
> > + const struct typec_altmode *partner =
> > + typec_altmode_get_partner(alt);
> > + dev_warn(&partner->dev,
> > + "EC does not support ap driven mode entry\n");
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + ret = cros_ec_cmd(data->port->typec_data->ec, 0, EC_CMD_TYPEC_CONTROL,
> > + &req, sizeof(req), NULL, 0);
> > +
> > + if (ret < 0)
> > + return ret;
> > +
> > + svdm_version = typec_altmode_get_svdm_version(alt);
> > + if (svdm_version < 0)
> > + return svdm_version;
> > +
> > + data->header = VDO(data->sid, 1, svdm_version, CMD_EXIT_MODE);
> > + data->header |= VDO_OPOS(data->mode);
> > + data->header |= VDO_CMDT(CMDT_RSP_ACK);
> > +
> > + data->vdo_data = NULL;
> > + data->vdo_size = 1;
> > +
> > + schedule_work(&data->work);
> > +
> > + return ret;
> > +}
> > +
> > +static int cros_typec_displayport_vdm(struct typec_altmode *alt, u32 header,
> > + const u32 *data, int count)
> > +{
> > + struct cros_typec_dp_data *dp_data = typec_altmode_get_drvdata(alt);
> > + struct cros_typec_altmode_data *adata = &dp_data->adata;
> > +
> > +
> > + int cmd_type = PD_VDO_CMDT(header);
> > + int cmd = PD_VDO_CMD(header);
> > + int svdm_version;
> > +
> > + if (!adata->ap_mode_entry) {
> > + const struct typec_altmode *partner =
> > + typec_altmode_get_partner(alt);
> > + dev_warn(&partner->dev,
> > + "EC does not support ap driven mode entry\n");
> > + return -EOPNOTSUPP;
> > + }
>
> Move the ckeck to cros_typec_altmode_vdm() ?
>
> But this makes me wonder, should the driver use different ops in such a
> case? Can't we just use a stubbed version of ops if
> cros_typec_register_displayport() gets ap_mode_entry = false ?
>
I could leave out `.vdm` in typec_altmode_ops and I'd get the same
result (-ENOTSUPP) but without the warning message. That'll remove the
need to store the bool entirely. Expect it next series -- thanks!
> > +
> > + svdm_version = typec_altmode_get_svdm_version(alt);
> > + if (svdm_version < 0)
> > + return svdm_version;
> > +
> > + switch (cmd_type) {
> > + case CMDT_INIT:
> > + if (PD_VDO_SVDM_VER(header) < svdm_version) {
> > + typec_partner_set_svdm_version(adata->port->partner,
> > + PD_VDO_SVDM_VER(header));
> > + svdm_version = PD_VDO_SVDM_VER(header);
> > + }
> > +
> > + adata->header = VDO(adata->sid, 1, svdm_version, cmd);
> > + adata->header |= VDO_OPOS(adata->mode);
> > +
> > + /*
> > + * DP_CMD_CONFIGURE: We can't actually do anything with the
> > + * provided VDO yet so just send back an ACK.
> > + *
> > + * DP_CMD_STATUS_UPDATE: We wait for Mux changes to send
> > + * DPStatus Acks.
> > + */
> > + switch (cmd) {
> > + case DP_CMD_CONFIGURE:
> > + dp_data->data.conf = *data;
> > + adata->header |= VDO_CMDT(CMDT_RSP_ACK);
> > + dp_data->configured = true;
> > + schedule_work(&adata->work);
> > + break;
> > + case DP_CMD_STATUS_UPDATE:
> > + dp_data->pending_status_update = true;
> > + break;
> > + default:
> > + adata->header |= VDO_CMDT(CMDT_RSP_ACK);
> > + schedule_work(&adata->work);
> > + break;
> > + }
> > +
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int cros_typec_altmode_vdm(struct typec_altmode *alt, u32 header,
> > + const u32 *data, int count)
> > +{
> > + struct cros_typec_altmode_data *adata = typec_altmode_get_drvdata(alt);
> > +
> > + if (adata->sid == USB_TYPEC_DP_SID)
> > + return cros_typec_displayport_vdm(alt, header, data, count);
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static const struct typec_altmode_ops cros_typec_altmode_ops = {
> > + .enter = cros_typec_altmode_enter,
> > + .exit = cros_typec_altmode_exit,
> > + .vdm = cros_typec_altmode_vdm,
> > +};
> > +
> > +#if IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
> > +int cros_typec_displayport_status_update(struct typec_altmode *altmode,
> > + struct typec_displayport_data *data)
> > +{
> > + struct cros_typec_dp_data *dp_data =
> > + typec_altmode_get_drvdata(altmode);
> > + struct cros_typec_altmode_data *adata = &dp_data->adata;
> > +
> > + if (!dp_data->pending_status_update) {
> > + dev_dbg(&altmode->dev,
> > + "Got DPStatus without a pending request");
> > + return 0;
> > + }
> > +
> > + if (dp_data->configured && dp_data->data.conf != data->conf)
> > + dev_dbg(&altmode->dev,
> > + "DP Conf doesn't match. Requested 0x%04x, Actual 0x%04x",
> > + dp_data->data.conf, data->conf);
> > +
> > + dp_data->data = *data;
> > + dp_data->pending_status_update = false;
> > + adata->header |= VDO_CMDT(CMDT_RSP_ACK);
> > + adata->vdo_data = &dp_data->data.status;
> > + adata->vdo_size = 2;
> > +
> > + schedule_work(&adata->work);
> > + return 0;
> > +}
> > +
> > +struct typec_altmode *
> > +cros_typec_register_displayport(struct cros_typec_port *port,
> > + struct typec_altmode_desc *desc,
> > + bool ap_mode_entry)
> > +{
> > + struct typec_altmode *alt;
> > + struct cros_typec_altmode_data *data;
> > +
> > + alt = typec_port_register_altmode(port->port, desc);
> > + if (IS_ERR(alt))
> > + return alt;
> > +
> > + data = devm_kzalloc(&alt->dev, sizeof(*data), GFP_KERNEL);
> > + if (!data) {
> > + typec_unregister_altmode(alt);
> > + return ERR_PTR(-ENOMEM);
> > + }
> > +
> > + INIT_WORK(&data->work, cros_typec_altmode_work);
> > + data->alt = alt;
> > + data->port = port;
> > + data->ap_mode_entry = ap_mode_entry;
> > + data->sid = desc->svid;
> > + data->mode = desc->mode;
> > +
> > + typec_altmode_set_ops(alt, &cros_typec_altmode_ops);
> > + typec_altmode_set_drvdata(alt, data);
> > +
> > + return alt;
> > +}
> > +#endif
> > diff --git a/drivers/platform/chrome/cros_typec_altmode.h b/drivers/platform/chrome/cros_typec_altmode.h
> > new file mode 100644
> > index 000000000000..c6f8fb02c99c
> > --- /dev/null
> > +++ b/drivers/platform/chrome/cros_typec_altmode.h
> > @@ -0,0 +1,34 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +
> > +#ifndef __CROS_TYPEC_ALTMODE_H__
> > +#define __CROS_TYPEC_ALTMODE_H__
> > +
> > +struct cros_typec_port;
> > +struct typec_altmode;
> > +struct typec_altmode_desc;
> > +struct typec_displayport_data;
> > +
> > +#if IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
> > +struct typec_altmode *
> > +cros_typec_register_displayport(struct cros_typec_port *port,
> > + struct typec_altmode_desc *desc,
> > + bool ap_mode_entry);
> > +
> > +int cros_typec_displayport_status_update(struct typec_altmode *altmode,
> > + struct typec_displayport_data *data);
> > +#else
> > +static inline struct typec_altmode *
> > +cros_typec_register_displayport(struct cros_typec_port *port,
> > + struct typec_altmode_desc *desc,
> > + bool ap_mode_entry)
> > +{
> > + return typec_port_register_altmode(port->port, desc);
> > +}
> > +
> > +static inline int cros_typec_displayport_status_update(struct typec_altmode *altmode,
> > + struct typec_displayport_data *data)
> > +{
> > + return 0;
> > +}
> > +#endif
> > +#endif /* __CROS_TYPEC_ALTMODE_H__ */
> > --
> > 2.47.0.277.g8800431eea-goog
> >
>
> --
> With best wishes
> Dmitry
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